Spring bolt



Feb. 1966 D. c. UTTERBACK- 3,233,932

SPRING BOLT Filed Oct. 15, 1963 w we 1 J, g V AM V ZQBG NB 655,. n. N. 4 5 I .o D A o .6 6 l4 0 M m w? 1 2,8 WW 1 u. m Q n a 9 .L mu We 5 l m m M 4 5 m 4 ATTOE V United States Patent Ofilice Patented Feb. 8, 1966 3,233,932 SPRING BOLT Denny C. Utterback, Miami Springs, Fla, assignor to Warren Industries, Inc., Hialeah, Fla, a corporation of Florida Filed Oct. 15, 1963, Ser. No. 316,221 6 Claims. (Cl. 292-175) This invention relates to a spring bolt of the general type adapted for axial movement, to engage in recesses in window casings or the like, for such purposes as holding a window or door screen panel in place, or holding a window sash in adjusted position. As ordinarily employed, such bolts usually partake of the form of a telescoping unit, with an outer, tubular, female member, and a headed, inner, male shank, having a headed end, and 'a surrounding spring acting against the headed end and a suitable shoulder on the female portion. As thus con- .stituted, the bolt is utilized by providing a suitable bore in the frame of the sash or screen panel, etc., and securing the bolt unit therein, against axial movement, by any suitable means, such as a driven, friction fit, or by a lateral locking pin, or snap ring or other means. According to the invention, a spring bolt is provided in which the outer tubular member, or female element is eliminated, the receiving opening in the item to be fastened serving in lieu of such female element. It is therefore a general object of the invention to simplify spring bolts, and more particularly, to eliminate a major element thereof, while retaining its function. In still greater particular, it is an object to eliminate the outer tube in axially reciprocable spring bolts.

In the use of the fastened item as the female element of the bolt or fastener, it becomes necessary to effect final assembly of the bolt by introducing separate parts thereof from opposite sides of the receiving opening, and thereafter uniting the said parts, and it is another eneral object of the invention to facilitate such a process. Also, since it is not only impractical, but unfeasible, to use machine operations to join the said parts, it is yet another object of the invention to provide a ready coupling means, capable of easy, manual operation. A further object is to provide a coupling means in which the parts are permanently joined against subsequent separation, in a simple, telescopic movement of translation, axially of the bolt parts. In particular, it is an object to provide a twopart bolt of plastic material, having a headed shank with an annular groove, and a separate handie, or knob, having a rib deformable radially to pass over said shank for ultimate, locked deposit in the groove, the shank having a frusto-conical portion for camming said rib to deform it radially.

These and other objects, which will be apparent, are attained by the present invention, a preferred form of which is described in the following specification, as illustrated in the drawing, in which:

FIGURE 1 is a perspective view of a corner fragment of a screen panel in place in a window casing, and employing a spring bolt according to the invention,

FIGURE 2 is an axial sectional view through the bolt, taken on the plane of the line 2-2 of FIGURE 1,

FIGURE 3 is a View generally similar to that of FIG- URE 2, showing the bolt in retracted position, and

FIGURE 4 is a bracketed view, in perpsective, showing, "in exploded form, the bolt parts in relation to the frame of the screen panel.

Referring to the drawings by characters of reference there is shown generally at It), a window casing, in which is lodged a screen panel having a screen 12, carried by a rectangular, metal frame 14, the particular form of which forms no part of the present invention, except insofar as it is provided with suitable openings to receive the bolt. Thus, the particular frame shown is tubular, and of generally rectangular cross section, with an outer edge face 16, and opposite, inner edge face 18, an exterior face 21), and an interior face 22. The latter is bent to form a channel cavity 24, with outer, side wall 26, bottom 28, and inner, side wall 30. So much of the frame is conventional, and the channel 24 is intended to receive the outer edges of screen 12, and the holding strips 32. For cooperation with the bolt, next to be described, the walls 16, 26, and 18 of the frame have axially aligned, circular openings 34, 36, 38 and 40, the latter three being about equal in diameter, and opening 34 being somewhat larger in diameter than the other three, for a purpose which will presently appear.

As seen in FIGURE 4, the bolt comprises three parts, namely, a headed shank 42, a knob 44, and a compression coil spring 46. Considered in detail, shank 42 has a main, cylindrical section 48, an outer, enlarged or headed, cylindrical portion 50, with frusto-conical, forward end 52, the headed portion being intended for engagement in a cylindrical recess in casing 10, as reinforced by a metal tube or liner 54, and the tapered end being intended to provide ready finding, and access to the recess. It will be understood that this headed portion may be varied in size, proportions, and arrangement to comport with changes in the other cooperating parts. At its inner end, the main section 48 of the shank has an annular groove 56, which, in the preferred embodiment shown, is of rectangular cross-section, but which may be varied in form within reasonable limits without sacrifice of the main benefits of the invention. For instance, the groove could be of curvilinear section, or have one or both side walls slanting. In an important feature of the invention, the end portion 58 of shank section 43, outwardly of groove 56 has a tapering form, with outwardly diminishing radius, in order to provide a camming action in the mounting of knob 44, and in the preferred embodiment shown this end is frusto-conical in form.

As seen in FIGURES 2 and 3, shank section 48 has a loose, sliding fit in the three similar openings 36, 38, 40, and the shank head 50 has a loose, sliding fit in the larger opening 34. When thus mounted, the coil spring 46 abuts the shoulder on head 50 at one end, and the channel wall 26 of the screen frame at the other. In the retracted position shown in FIGURE 3 the head 50 has passed inbolt captive, the coupling action being irreversible.

wardly away from opening 34, and the tapered end 52 of the head aids the head in regaining the opening, on return movement, in spite of any slight degree of wobble which might be due to the short length of the bearing surfaces afforded by openings 36, 38 and 40, and the looseness of the fit therein.

As stated above, the hollow frame is merely an illustration of one environmental use of the bolt, which could also be mounted, for instance in a solid frame of wood or metal, having a bore equivalent in size to openings 36, 38 and 40, and a counterbore equivalent in size to opening 34.

Whatever the form of the holding frame, the spring 46 is slipped over shank section 48, and the thus combined parts are passed through the large opening, with the shank section 48 passing on through the smaller opening or openings, after which the knob 44 is snapped onto the protruding, inner end of the bolt shank, rendering the To this end, the knob, which has a long, tapering shank 60, with an annular, cylindrical rib 62 at one end, forming a head, for ready grasping by the fingers for the reciprocat ing movement against spring 46 during use, has an internal bore 64, with a radially inwardly extending rib 66, adapted to be received in the groove 56 in the shank 48.

For ready mounting the inner edge of bore 64 is preferably chamfered. The inner diameter of rib 66 is smaller than the major diameter at the base of frusto-conical end 58 of the bolt shank, and the differential will be such as to just enable sufficient deformation at the corner of the base of the cone, to pass the rib, having in mind the physical characteristics of the plastic material of the bolt, and the available assembly pressure. In one important use, the bolts are utilized in connection with existing frames, after the boring of suitable holes, and the arrangement is such that the bolt may be assembled on the frame by a serviceman, or home mechanic, by simple, manual pressure.

As in the case of the groove 56, the rib 66 may be provided in cross-sectional forms other than that shown,

.for instance, triangular, truncated wedge-form, or arcuate,

and, likewise, the tapered end 58 may be curvilinear in section, rather than straight sided.

In the preferred form of the device, the material of both the shank and the knob is nylon, but other types of plastic material may be employed to good advantage in the attainment of the easy snap-on feature,vtogether with tenacious coupling. Using nylon as the material, the practice of the invention is found to be most facile when the parts are dimensioned in ratios such that a shank 48 of 0.125 inch diameter hasa groove 56 with a bottom 0.095 inch diameter, the frusto-conical head 58, slanted 30 to the axis of the bolt, has a maximum, or base diameter of 0.115 inch, and the rib 66 has an inner diameter of 0.106 inch. The base of the frusto-conical head 53 is thus 0.009 inch greater in diameter than the inner diameter of rib 66, which means that a radial excess of 0.0045 inch at the outer edge region of the base must be overcome in snapping the knob into place. The neces sary adjustment is provided by the elasticity of the material, and is accomplished partly by bending of the outer edge of the cone base, and partly by radial expansion of rib 66. The width of rib 66 is preferably only slightly less than that of groove 56, and the axialbore 64 of knob 44 is such as to provide a snug, or slightly loose, sliding fit on shank section or stem 48. The head is revolvable on stem 48 after being locked in its mounted position, but this is immaterial, since the bolt action is in an axial direction only.

While a certain, preferred embodiment has been shown and described, various modifications will be apparent, in the light of this disclosure, and the invention should not, therefore, be deemed as limited, except insofar as shall appear from the spirit and scope of the appended claims.

I claim:

1. A composite, spring bolt, of plastic material, preferably nylon, latching objects in position by axial movement, and adapted for assembly in situ, in suitable openings in said objects, and comprising a cylindrical shank having a stem of uniform diameter, and having a headed portion, at one end, of uniform diameter, with a frustoconical, outer edge, and defining a shoulder with said stem, a coil compression spring surrounding said stem, and adapted to abut said shoulder in end reaction, said :stem having an annular groove near its other end, of rectangular cross section, and a frusto-conical end portion of outwardly diminishing radius beyond said groove, and a knob having a frusto-conical, inner portion, and a radially extended, cylindrical, outer portion, and having an axial bore of constant radius, adapted for sliding fit on said stem, and a radially inwardly extending rib, of rectangular cross section, in said bore, in the region of said cylindrical portion, adapted to be received in said groove, the inner diameter of said rib being greater than the diameter of the base of said groove, and less than the maximum diameter at the base of said frusto-conical end portion of said stern.

2. A composite, spring bolt, of nylon plastic material, for latching objects in position by axial movement, and

adapted for assembly in situ, in suitable openings in said objects, and comprising a cylindrical shank having a stem of uniform diameter, and having a headed portion, at one end, of uniform diameter, with a frusto-conical outer edge, and defining a shoulder with said stem, a coil compression spring surrounding said stem, and adapted to abut said shoulder in end reaction, said stem having an annular groove near its other end, of rectangular cross section, and a frusto-conical end portion of outwardly diminishing radius beyond said groove, and a knob having an axial bore adapted for a sliding fit on said stem, and having a radially inwardly extending rib of rectangular cross section in said bore, adapted to be received in said groove, the inner diameter of said rib being greater than the diameter of the base of said groove, and less than the maximum diameter at the base of said frustoconical end portion.

3. A composite, spring bolt, of nylon plastic material, for latching objects in position by axial movement, and adapted for assembly in situ, in suitable openings in said objects, and comprising a cylindrical shank having a stem of uniform diameter, and having a headed portion at one end, of uniform diameter, with a frusto-conical, outer edge, and defining a shoulder with said stem, said stem adapted to receive a coil compression spring, in abutting relation to said shoulder in end reaction, said stem having an annular groove near its other end, of rectangular cross section, and a frusto-conical end portion of outwardly diminishing radius beyond said groove, and a knob having an axial bore adapted for a sliding fit on said stem, and having a radially inwardly extending rib of rectangular cross section in said bore, adapted to be received in said groove, the inner diameter of said rib being greater than the diameter of the base of said groove, and less than the maximum diameter at the base of said frusto-conical end portion.

4, A composite, spring bolt, of nylon plastic material, for latching objects in position by axial movement, and adapted for assembly in situ, in suitable openings in said objects, and comprising a cylindrical shank having a stern, and a headed portion, at one end, with a frusto-conical, outer edge, and defining a shoulder with said stem, said stem adapted to receive a coil compression spring, in abutting relation to said shoulder in end reaction, said stem having an annular groove near its other end, of rectangular cross section, and a frusto-conical end portion of outwardly diminishing radius beyond said groove, and a knob having an axial bore adapted for a sliding fit on said stem, and having a radially inwardly extending rib of rectangular cross section in said bore, adapted to be received in said groove, the inner diameter of said rib being greater than the diameter of the base of said groove, and less than the maximum diameter at the base of said frusto-conical end portion.

5. A composite, spring bolt, of nylon plastic material, for latching objects in position by axial movement, and adapted for assembly in situ, in suitable openings in said objects, and comprising a cylindrical shank having a stem, and a headed portion, at one end, with a frusto-conical, outer edge, and defining a shoulder with said stem, said stern adapted to receive a coil compression spring, in abutting relation to said shoulder in end reaction, said stem having an annular groove near its other end, and a frusto-conical end portion of outwardly diminishing radius beyond said groove, and a knob having an axial bore adapted for a sliding fit on said stem, and having a radial ly inwardly extending rib in said bore, adapted to be received in said groove, the inner diameter of said rib being greater than the diameter of the base of said groove, and less than the maximum diameter at the base of said frusto-conical end portion.

6. A composite, spring bolt, of nylon plastic material, for latching objects in position by axial movement, and adapted for assembly in situ, in suitable openings in said objects, and comprising a cylindrical shank having a stem, and a headed portion, at one end, with a tapering, outer edge, and defining a shoulder with said stem, said stern adapted to receive a coil compression spring, in abutting relation to said shoulder in end reaction, said stem having an annular groove near its other end, and a tapering end portion of outwardly diminishing radius beyond said groove, and a knob having an axial bore adapted for a sliding fit on said stem, and having a radially inwardly extending rib in said bore, adapted to be received in said groove, the inner diameter of said rib being greater than the diameter of the base of said groove, and less than the maximum diameter at the base of said tapering end portion.

References Cited by the Examiner UNITED STATES PATENTS Motley 292175 Hawthorne 292-175 Oswald et a1 292-175 Michael 292-347 Hensel 292153 Herr et a1 16-121 JOSEPH D. SEERS, Primary Examiner.

M. HENSON WOOD, 1a., Examiner.

J. R. MOSES, Assistant Examiner. 

2. A COMPOSITE, SPRING BOLT, OF NYLON PLASTIC MATERIAL, FOR LATCHING OBJECTS IN POSITION BY AXIAL MOVEMENT, AND ADAPTED FOR ASSEMBLY IN SITU, IN SUITABLE OPENINGS IN SAID OBJECTS, AND COMPRISING A CYLINDRICAL SHANK HAVING A STEM OF UNIFORM DIAMETER, AND HAVING A HEADED PORTION, AT ONE END, OF UNIFORM DIAMETER, WITH A FRUSTO-CONICAL OUTER EDGE, AND DEFINING A SHOULDER WITH SAID STEM, A COIL COMPRESSION SPRING SURROUNDING SAID STEM, AND ADAPTED TO ABUT SAID SHOULDER IN END REACTION, SAID STEM HAVING AN ANNULAR GROOVE NEAR ITS OTHER END, OF RECTANGULAR CROSS SECTION, AND A FRUSTO-CONICAL END PORTION OF OUTWARDLY DIMINISHING RADIUS BEYOND SAID GROOVE, AND A KNOB HAVING AN AXIAL BORE ADAPTED FOR A SLIDING FIT ON SAID STEM, AND HAVING A RADIALLY INWARDLY EXTENDING RIB OF RECTANGULAR CROSS SECTION IN SAID BORE, ADAPTED TO BE RECEIVED IN SAID GROOVE, THE INNER DIAMETER OF SAID GROOVE, AND LESS THAN THE DIAMEWTER OF THE BASE OF SAID GROOVE, AND LESS THAN THE MAXIMUM DIAMETER AT THE BASE OF SAID FRUSTOCONICAL END PORTION. 